Purpose: This study summarizes findings from objective assessments of compliance (or adherence) and persistence with ocular hypotensive agents in patients with glaucoma and ocular hypertension.Design: Systematic literature review.Methods: A PubMed and reference list search was conducted across publication years 1970–2010, using these terms and variants: "compliance," the equivalent term "adherence," and "persistence" in patients with these conditions and therapies. Summaries of selected studies were stratified by measurement method (electronic monitor, prescription fills review, medical chart review). Measures of central tendency across studies were calculated for commonly-reported compliance or persistence measures.Results: Fifty-eight articles met all inclusion/exclusion criteria: measurement of compliance–electronic monitoring (seven studies reported in 14 articles), measurement of compliance/persistence–prescription records (36 studies in 38 articles), and measurement of persistence–medical chart review (six studies in six articles). From electronic monitoring, most therapy-experienced patients took medication consistently, but ≥20% met criteria for poor compliance. From prescription records, only 56% (range 37%–92%) of the days in the first therapy year could be dosed with the medication supply dispensed over this period. At 12 months from therapy start, only 31% (range 10%–68%) of new therapy users had not discontinued, and 40% (range 14%–67%) had not discontinued or changed the initial therapy. From medical chart review, only 67% (range 62%–78%) of patients remained persistent 12 months after starting therapy.Conclusions: Evidence provided by this review suggests that poor compliance and persistence has been and remains a common problem for many glaucoma patients, and is especially problematic for patients new to therapy. The direction of empirical research should shift toward a greater emphasis on understanding of root causes and identification and testing of solutions for this problem.